杉木、柳杉与黄连间作的初步研究

引言林农间作、林药间作等混农林业模式是提高农、林业生态系统功能和生产的有效途径。我国耕地面积小,森林资源不足,因此发展混农林业生产,最大限度地利用林地生产力,提     

高黎贡山地区户级水平混农林系统农业生物多样性评价——以百花岭汉龙社为例

本文概述了汉龙社混农林系统及其发展过程。选取了六个农户的核桃和板栗混农林系统进行了农业生物多样性调查与分析 ,结果表明 :不同农户的混农林系统之间物种丰富度、农业物种丰富度、物种利用率和个体利用率都存在差异。混农林系统中个体利用率较小而物种利用率相对较大。物种丰富度指数平均值为 0 0 5 2 ,其中最大的比平均值高 2 1 % ,最小的比平均值低 2 9% ;农业物种丰富度指数平均值 0 1 92 ,最大的比平均值高5 1 % ,最小的比平均值低 4 9% ,差异性较大。通过物种丰富度与经济效益比较 ,具有较高物种丰富度和农业物种丰富度的混农林系统 ,经济效益也较高 ,充分体现了混农林系统的生态、经济和社会三大效益     

林农复合经营生态体系的研究

林农复合经营以生态经济学的原理,运用现代生物和生态工程方法技术,组成林、农、牧、副、渔有机结合的复合生产体系。它突破了传统林业的单一生产方式,形成以林为主的一个复合的、开放的、具有整体效应的生态系统。这种复合系统能有效地提高土地资源利用率,促进太阳能和有关物质在系统内的多次循环利用,实现整个系统在空间和时间上的高效利用。多年来的研究表明,这种由多种产业部     

林业资源管理对生态环境影响的研究

对林业资源进行合理地开发利用,不仅能有效地促进社会经济的发展,也能改善我们的生态环境,缓解空气和水资源的污染。但是,目前我国林业资源的利用率存在很多的问题和缺陷,我们应如何对林业资源进行开发和利用是目前亟需解决的问题。     

中国农林业害虫分布特征及其影响因素

我国农、林业虫害危害范围和程度日益加剧,给生态环境和国民经济带来严重影响。本文根据文献记录和野外调查,系统整理了全国农、林业植物检疫性害虫分布特征,并用主成分分析、相关分析和回归分析方法,探讨了气象因素和社会经济因素对我国省级单位空间中农林业害虫分布的影响。结果表明,我国农林业虫害数量和密度分布总体上呈现由东部沿海向西部内陆减少的趋势。导致这一格局的主要因子是农业、经济发展水平因子,其次是温湿度等气象因子,说明农用地面积大、农作物播种面积大、森林覆盖率高、地区生产总值高、运输线路长、温度高湿度大的地区是害虫发生、发展的重灾区,也是潜在分布的高频区,应该引起政府管理部门的重视,积极采取防治措施。     

施肥对小老树光合速率及水分利用率的影响

不同施肥对小时杨小老树光合速率、蒸腾速度、单叶面积均有明显的提高作用,水分利用率则表现出明显差异,随施磷肥量增加,光合作用增加明显而蒸腾作用基本一致,水分利用率则上升明显,Ｎ肥处理则水分利用率下降。Ｎ、Ｐ混施叶面积增加明显。     

浙江省出版“科学技術”半月刊

一件值得浙江农友们和浙江人民高兴的事是该省“科学技术”最近于七月五日正式创刊,并在五月二十五发了一期试刊号,试刊的目的是为了更好的办好此刊。“科学技术”是浙江省农业厅、林业厅、卫生厅和科学普及协会联合创办的通俗农村科学技术刊物。它专门介绍农业、林业生产的科学技术知识,交流各地农、林业生产的先进     

食用菌生产率研究

利用微生物的巨大潜力提高蛋白质的生产率即--把农、林业废料木质纤维素通过微生物降解后培养富含生物蛋白的食用菌,并利用菌渣(含45％生物蛋白)作饲料添加剂从而取得很高的经济效益的良性循环的生产模式应当引起重视。我国每年可供利用的食用、药用菌的培养基-农、林业木质纤维废料估计最少为200亿斤,如充份加以利用可以取得良性循环的效果。     

植物对虫害的超越补偿作用

阐述了超越补偿作用的本质及其生物学机制,并探讨了超越补偿在生理生态学及栽培学方面的意义,为超越补偿理论在农作物栽培和农、林害虫防治等方面的应用提供科学依据,以进一步提高农、林业生产的经济效益。     

现代林业发展和林业技术的关系

随着我国经济的快速发展,我国的林业领域也得到了飞速的发展,并成为了我国非常重要的支柱性产业。但是就当前我国的林业方面来看,依然存在着很多的问题,如人均自然资源较少、树木的利用效率较低以及森林面积不断减少等。为了有效的解决这些问题,提高森林的利用率,就要在林业发展过程中科学的应用林业技术,摄取最新的专业知识。因此,本文主要围绕林业发展和林业技术之间的关系,有针对性的提出一些措施,从而促进我国绿色林业的稳步发展。     

On optimal delivery of combination therapy for tumors

A mathematical model for the scheduling of angiogenic inhibitors in combination with a chemotherapeutic agent is formulated. Conditions are given that allow tumor eradication under constant infusion therapies. Then the optimal scheduling of a vessel disruptive agent in combination with a cytotoxic drug is considered as an optimal control problem. Both theoretical and numerical results on the structure of optimal controls are presented.     

Nonlinear Blending: A Useful General Concept for the Assessment of Combination Drug Synergy

Human diseases may involve cellular signaling networks that contain redundant pathways, so that blocking a single pathway in the system cannot achieve the desired effect. As such, the use of drugs in combination are particularly effective interventions in networked systems. However, common synergy measures are often inadequate to quantify the effect of two different drugs in complex cellular systems. This article proposes a general approach to quantifying the synergy of two drugs in combination. This approach is called strong nonlinear blending. Drugs with different relative potencies, different effect maxima, or situations of potentiation or coalism pose no problem for strong nonlinear blending as a way to assess the increased response benefit to be gained by combining two drugs. This is important as testing drug combinations in complex biological systems are likely to produce a wide variety of possible response surfaces. It is also shown that for monotone increasing (or decreasing) dose response surfaces that strong nonlinear blending is equivalent to improved potency along a ray of constant dose ratio. This is important because fixed dose ratios form the basis for many preclinical and clinical combination drug experiments. Two examples are given involving HIV and cancer chemotherapy combination drug experiments.     

Statistical Methods for Integrating Randomized Clinical Studies for Evaluation of Combination Treatment Therapy

In regulatory applications, evaluation of a combination drug at a fixed dose is based on pairwise comparisons of the combination with its component drugs. These comparisons generate the least expected gain of the combination relative to its components as the key effect parameter for evaluation. Two test methods are developed for the evaluation to combine multiple clinical studies that are deemed combinable. One test method is based on a linear combination of the Min tests from individual studies. In the other test method, weighted estimators are first derived for the pairwise comparisons between the combination and the respective components by combining the studies. A Min test is then applied to these estimators. The latter test method tends to be more powerful than the former test method. A test-based confidence interval is constructed for the least expected gain of the combination relative to its components. A test for heterogeneity across studies is also developed.     

Reaction of nitric oxide with heme proteins and model compounds of hemoglobin

Rates for the reaction of nitric oxide with several ferric heme proteins and model compounds have been measured. The NO combination rates are markedly affected by the presence or absence of distal histidine. Elephant myoglobin in which the E7 distal histidine has been replaced by glutamine reacts with NO 500-1000 times faster than do the native hemoglobins or myoglobins. By contrast, there is no difference in the CO combination rate constants of sperm whale and elephant myoglobins. Studies on ferric model compounds for the R and T states of hemoglobin indicate that their NO combination rate constants are similar to those observed for the combination of CO with the corresponding ferro derivatives. The last observation suggests that the presence of an axial water molecule at the ligand binding site of ferric hemoglobin A prevents it from exhibiting significant cooperativity in its reactions with NO.     

Mechanism of uncoupling by uncouples of oxidative phosphorylation

Classical uncouplers duplicate exactly the uncoupling actions of the valinomycin-nigericin ionophoric combination in presence of K⁺ — a combination that mediates cyclical transport of K⁺ driven by electron transfer or pyrophosphorolysis of ATP in mitochondria. Evidence has been presented that uncouplers have the properties essential for mediating coupled cyclical transport of cations and that uncoupling of oxidative phosphorylation can be rationalized in terms of one coupled process being displaced and replaced by another. The critical demonstrations were first that uncoupling is a cation-dependent process and that only those cations that can undergo complexation with uncouplers are effective in restoring mitochondrial uncoupler action in a cation-deficient medium. The second demonstration was that uncouplers are ionophores, not only of the nigericin type but also of the valinomycin type (electrogenic). This combination in one molecule of electrogenic as well as non-electrogenic ionophoric activity for cations endows uncouplers with the capability for duplicating the uncoupling action of the valinomycin-nigericin combination and for mediating coupled cyclical transport of cations.     

Nonlinear blending: a useful general concept for the assessment of combination drug synergy

Human diseases may involve cellular signaling networks that contain redundant pathways, so that blocking a single pathway in the system cannot achieve the desired effect. As such, the use of drugs in combination are particularly effective interventions in networked systems. However, common synergy measures are often inadequate to quantify the effect of two different drugs in complex cellular systems. This article proposes a general approach to quantifying the synergy of two drugs in combination. This approach is called strong nonlinear blending. Drugs with different relative potencies, different effect maxima, or situations of potentiation or coalism pose no problem for strong nonlinear blending as a way to assess the increased response benefit to be gained by combining two drugs. This is important as testing drug combinations in complex biological systems are likely to produce a wide variety of possible response surfaces. It is also shown that for monotone increasing (or decreasing) dose response surfaces that strong nonlinear blending is equivalent to improved potency along a ray of constant dose ratio. This is important because fixed dose ratios form the basis for many preclinical and clinical combination drug experiments. Two examples are given involving HIV and cancer chemotherapy combination drug experiments.     

Optimal species distinction by discriminant analysis: comparing established methods of character selection with a combination procedure using ant morphometrics as a case study

We compare the performances of established means of character selection for discriminant analysis in species distinction with a combination procedure for finding the optimal character combination (minimum classification error, minimum number of required characters), using morphometric data sets from the ant genera Cardiocondyla , Lasius and Tetramorium . The established methods are empirical character selection as well as forward selection, backward elimination and stepwise selection of discriminant analysis. The combination procedure is clearly superior to the established methods of character selection, and is widely applicable.     

Surface disinfection properties of the combination of an antimicrobial peptide,ranalexin, with an endopeptidase,lysostaphin, against methicillin‐resistant Staphylococcus aureus (MRSA)

Aims: To characterize the antibacterial synergy of the antimicrobial peptide, ranalexin, used in combination with the anti‐staphylococcal endopeptidase, lysostaphin, against methicillin‐resistant Staphylococcus aureus (MRSA), and to assess the combination’s potential as a topical disinfectant or decolonizing agent for MRSA. MRSA causes potentially lethal infections, and pre‐operative patients colonized with MRSA are often treated with chlorhexidine digluconate and mupirocin cream to eradicate carriage. However, chlorhexidine is unsuitable for some patients, and mupirocin resistance is increasingly encountered, indicating new agents are required. Methods and Results: Using an ex vivo assay, ranalexin and lysostaphin tested in combination reduced viable MRSA on human skin to a greater extent than either compound individually. The combination killed bacteria within 5 min and remained effective and synergistic even in high salt and low pH conditions. Conclusions: The combination is active against MRSA on human skin and under conditions that may be encountered in sweat. Significance and Impact of the Study: Although the exact mechanism of activity remains unresolved, considering its specific spectrum of activity, fast killing kinetics and low likelihood of resistance arising, the combination of ranalexin with lysostaphin warrants consideration as a new agent to eradicate nasal and skin carriage of Staph. aureus, including MRSA.     

蛋白免疫印迹法同时检测大、小分子蛋白的实验条件改进

目的:蛋白免疫印迹法是现代生物医学研究中广泛应用于蛋白定性和半定量分析的实验技术。然而,常规采用传统单一浓度凝胶的蛋白免疫印迹法在应用过程中仍有不足之处,如不能同时检测分子量很大和很小的蛋白,因而有必要探索一种增大凝胶有效分离范围的检测方法。本文提出采用组合凝胶来实现更大范围分子量蛋白的同时检测。方法:比较双浓度的组合凝胶与单一浓度凝胶的分离范围以及分析采用组合凝胶,蛋白免疫印迹法对大、小分子蛋白的检测效果。结果:12%/7.5%组合凝胶和15%/7.5%组合凝胶的分离范围显著大于相应的单一浓度凝胶。通过12%/7.5%组合凝胶,蛋白免疫印迹法同时检测到15-300 k Da范围内的大、小分子蛋白。结论:组合凝胶有助于蛋白免疫印迹法对分子量相差很大的蛋白进行同时检测分析,具有很强的实用性。     

The concept of the effective dose a proposal for the combination of organ doses

Irradiation of the human body by external or internal sources leads mostly to a simultaneous exposure of several organs. However, so far no clear and consistent recommendations for the combination of organ doses and the assessment of an exposure limit under such irradiation conditions are available. Following a proposal described in ICRP-publication 14 one possible concept for the combination of organ doses is discussed in this paper. This concept is based on the assumption that at low doses the total radiation detriment to the exposed person is given by the sum of radiation detriments to the single organs. Taking into account a linear dose-risk relationship, the sum of weighted organ doses leads to the definition of an "Effective Dose". The applicability and consequences of this "Effective Dose Concept" are discussed especially with regard to the assessment of the maximum permissible intake of radionuclides into the human body and the combination of external and internal exposure.